The present invention relates to vehicle-mounted devices, and more particularly to systems and methods for aligning vehicle-mounted devices with the drive axis of the vehicle.
Various devices on a vehicle are designed to be aligned to the vehicle's drive axis (both pointing in the forward drive direction and the rearward drive direction) in order to obtain optimum performance. Such devices can include, but are not limited to, cameras, radar sensors, lidar sensors, and headlights. It is known that aligning such devices to the drive axis gives the optimal performance, but sometimes the alignment is done to the body axis, with the assumption that the drive axis is parallel to the body axis (although there can be a difference up to about 3.0 degrees). Previously, a large and expensive machine, sometimes referred to as a “rolls machine,” present typically only at the vehicle assembly plant, was used to align these and other devices with the vehicle's drive axis. The machine lifts the vehicle on a set of powered rollers to allow the vehicle wheels to turn and to establish a natural drive path or drive axis while keeping the vehicle stationary. Once the drive axis has been determined, the devices are aligned to the drive axis at the assembly plant.
Another alignment system requires clamps to be mounted on the rear wheels, and the measuring of the angles formed between the clamps and a reference bar mounted on the ground. The average angle of the two rear wheels relative to the bar on the ground is used to set the angle of a mirror placed in front of the vehicle. The mirror is then used to align the vehicle-mounted devices (e.g., radar sensors). This system requires an expensive device for measuring and setting the angles of the mirror, expensive and cumbersome wheel clamps, and the mounting of a straight bar onto the ground without creating any torsion in the bar. While expensive and somewhat difficult to use, this system provides relatively accurate alignment, and is much more accurate than other less expensive prior art sensor alignment systems.